From 309e72be7035f54d7229f6f9b6930e7fe5c22feb Mon Sep 17 00:00:00 2001
From: HawkForge <75696486+HawkForge@users.noreply.github.com>
Date: Sat, 24 Oct 2026 17:45:23 +0600
Subject: [PATCH] Keep Scoop source placeholders valid across source reloads

Closes #4835
---
 .../Manager/Classes/SourceFactory.cs          | 18 +++++++--
 .../SourceFactoryTests.cs                     | 37 +++++++++++++++++++
 2 files changed, 52 insertions(+), 3 deletions(-)
 create mode 100644 src/UniGetUI.PackageEngine.Tests/SourceFactoryTests.cs

diff --git a/src/UniGetUI.PackageEngine.PackageManagerClasses/Manager/Classes/SourceFactory.cs b/src/UniGetUI.PackageEngine.PackageManagerClasses/Manager/Classes/SourceFactory.cs
index 49dda4391f..41a7a04bd8 100644
--- a/src/UniGetUI.PackageEngine.PackageManagerClasses/Manager/Classes/SourceFactory.cs
+++ b/src/UniGetUI.PackageEngine.PackageManagerClasses/Manager/Classes/SourceFactory.cs
@@ -7,6 +7,7 @@ public class SourceFactory : ISourceFactory
     {
         private readonly IPackageManager __manager;
         private readonly ConcurrentDictionary<string, IManagerSource> __reference;
+        private readonly ConcurrentDictionary<string, IManagerSource> __placeholders = [];
         private readonly Uri __default_uri = new("https://devolutions.net/unigetui");
 
         public SourceFactory(IPackageManager manager)
@@ -32,9 +33,11 @@ public IManagerSource GetSourceOrDefault(string name)
                 return source;
             }
 
-            ManagerSource new_source = new(__manager, name, __default_uri);
-            __reference.TryAdd(name, new_source);
-            return new_source;
+            IManagerSource new_source = __placeholders.GetOrAdd(
+                name,
+                n => new ManagerSource(__manager, n, __default_uri)
+            );
+            return __reference.GetOrAdd(name, new_source);
         }
 
         /// <summary>
@@ -60,6 +63,15 @@ public void AddSource(IManagerSource source)
                     existing_source.ReplaceUrl(source.Url);
                 }
             }
+
+            // Placeholders handed out before a Reset() are still referenced by packages
+            if (__placeholders.TryRemove(source.Name, out IManagerSource? placeholder))
+            {
+                if (placeholder.Url == __default_uri)
+                {
+                    placeholder.ReplaceUrl(source.Url);
+                }
+            }
         }
 
         public IManagerSource[] GetAvailableSources()
diff --git a/src/UniGetUI.PackageEngine.Tests/SourceFactoryTests.cs b/src/UniGetUI.PackageEngine.Tests/SourceFactoryTests.cs
new file mode 100644
index 0000000000..c1a14e9791
--- /dev/null
+++ b/src/UniGetUI.PackageEngine.Tests/SourceFactoryTests.cs
@@ -0,0 +1,37 @@
+using UniGetUI.PackageEngine.Interfaces;
+using UniGetUI.PackageEngine.Tests.Infrastructure.Builders;
+
+namespace UniGetUI.PackageEngine.Tests;
+
+public sealed class SourceFactoryTests
+{
+    [Fact]
+    public void PlaceholderHandedOutBeforeResetReceivesRealUrlFromAddSource()
+    {
+        var manager = new PackageManagerBuilder().Build();
+        var factory = manager.SourcesHelper.Factory;
+        IManagerSource placeholder = factory.GetSourceOrDefault("main");
+
+        factory.Reset();
+        var real = new SourceBuilder()
+            .WithManager(manager)
+            .WithName("main")
+            .WithUrl("https://github.com/ScoopInstaller/Main")
+            .Build();
+        factory.AddSource(real);
+
+        Assert.Equal(real.Url, placeholder.Url);
+    }
+
+    [Fact]
+    public void PlaceholderRequestedAfterResetIsTheSameInstanceAsBefore()
+    {
+        var manager = new PackageManagerBuilder().Build();
+        var factory = manager.SourcesHelper.Factory;
+        IManagerSource before = factory.GetSourceOrDefault("main");
+
+        factory.Reset();
+
+        Assert.Same(before, factory.GetSourceOrDefault("main"));
+    }
+}